Corresponding author:
Ghazal Norouzi, M.D. Assistant Professor of Nuclear Medicine and
Molecular Imaging
Address: Nuclear Medicine Department, Shohada-e Tajrish Medical
Center, Tajrish Square, Tehran, Iran. Tel: +982122723263 -
+989121183770 Fax: +982122723263 Email:ghazal.norouzi@sbmu.ac.ir
Author Contribution: All authors made substantial contribution
to collecting patient’s data and preparing this manuscript.
Acknowledgments: We thank the patient who graciously
collaborated with this study, her written informed consent was obtained
as well.
Financial Support: This work received no financial support and
no funding was provided to any of the authors.
Conflict of Interest: Authors have no conflict of interest to
disclose.
Data Availability: As no data sets were generated or analyzed
in the current study, data sharing is not applicable to this article.
Keywords: COVID-19 vaccines, adverse effects, subacute
thyroiditis, thyroiditis, COVID-19, SARS-CoV-2, side effects
Subacute Thyroiditis Following COVID-19 Vaccination
To the editor,
Subacute thyroiditis (SAT), also known as De Quervain’s thyroiditis, is
a self-limited inflammatory thyroid disorder presenting with radiating
neck pain, fever and a cluster of symptoms resulting from the
thyrotoxicosis caused by destruction of follicular epithelium and loss
of follicular integrity. Upper respiratory tract viral infections
antecede most SAT cases; supporting a post-viral inflammatory response
origin. Many viruses, such as influenza, adenovirus, and Coxsackie virus
have been identified as responsible pathogens1-4. With
the COVID-19 pandemic taking the world by storm, there have been a few
case reports on SAT following severe acute respiratory syndrome
coronavirus 2 (SARSCOV-2) infection1-2. To our
knowledge, SAT has not yet been reported as a result of COVID-19
vaccination in an otherwise healthy individual, regardless of the
vaccine type. We hereby describe a COVID-19 vaccine-related case of
subacute thyroiditis.
A 34-yr-old woman, with negative history of previous proven or
suspicious COVID-19 infection, received her first dose of COVAXIN (The
Bharat Biotech COVID-19 Vaccine) on April 3rd 2021,
with onset of expected symptoms, mainly fatigue, myalgia and mild fever
about 12 hours post-injection, gradually resolving over the next 72
hours. During the 5th-7th day post
vaccination, she experienced gradual onset of intermittent mild fever,
palpitation and radiating anterior neck pain, which she initially
thought of as extended post-vaccination symptoms. She consulted an
internal medicine specialist due to persistence of symptoms, 11 days
post-vaccination. At physical examination, the thyroid gland was tender
to touch and mildly enlarged, with no palpable thyroid nodule. The
patient had no history of prior thyroid disorder or any type of high
iodine exposure. She was referred for 99mTechnetium-pertechnetate
thyroid scintigraphy on the same day, demonstrating global, moderate to
severely decreased radiotracer uptake of the thyroid gland and increased
background activity; compatible with subacute thyroiditis (Fig.1). The
subsequently performed ultrasound examination revealed heterogeneity and
decreased vascularity of the thyroid gland. The simultaneously acquired
laboratory data portrayed thyrotoxicosis with suppressed thyrotropin
(TSH) and elevated free thyroxine (FT4), free triiodothyronine (FT3)
levels. Erythrocyte sedimentation rate and C-reactive protein levels
were high and borderline upper limit of normal, respectively (Table 1).
Subacute thyroiditis was confirmed; however, the patient had no history
upper respiratory tract infection or otherwise viral infection symptoms
during the past 3 months (except for the previously-described
post-vaccination symptoms), she had no history of recent travel during
the past couple of months and followed the social distancing rules
vigorously, having had no close or unprotected contact with any known or
suspected SARSCOV-2-positive case. Her concurrent chest CT scan
indicated that her lungs were clear with no sign of any current or prior
sequels of COVID-19 infection or other causes of pneumonia. Therefore,
it is logical to assume that in this case, SAT developed following the
inflammatory response to COVAXIN. As expected, the patient showed
satisfactory response to oral prednisolone treatment.
Having been associated with various strains of viruses, SAT is
recognized to have a viral, or to be more specific, post-viral
inflammatory response, origin1-4. To this date, a few
cases have been reported of SAT developing after influenza and H1N1
vaccination in healthy individuals with no history of prior viral upper
respiratory tract infection, suggesting that attenuated/inactivated
viral vaccines may rarely trigger SAT onset as well3,
4. The ongoing COVID-19 pandemic has urged countries all over the world
to eagerly pursue national vaccination programs, with multiple
pharmaceutical companies vigilantly developing, testing and modifying
new vaccines every day5. While there have been a few
reports on COVID-19-associated SAT1, 2, no similar
observation has been reported so far for COVID-19 vaccines, regardless
of vaccine type. The chronological events of our case suggest that
COVID-19 vaccination, in this case first dose of COVAXIN administration,
may be held accountable for SAT. The fact that SAT is generally an
underdiagnosed/misdiagnosed condition becomes more pronounced in
vaccine-related cases, since, as in our case, patients are more prone to
attribute SAT symptoms to expected flu-like post-vaccination
symptoms3, 4. It is not yet clear whether the type of
COVID-19 vaccine, in case of COVAXIN being an inactivated whole-virion
vaccine5, affects the chances of SAT development or
not. Nonetheless, we believe physicians should be alerted about the
possible association between SAT and COVID-19 vaccination, which even if
extremely rare, may translate to significant numbers considering the
large vaccinated population. Given that patients frequently experience
flu-like symptoms after COVID-19 vaccination, informing them well about
the expected nature and duration of symptoms, advising them to consult
their physician if experiencing anterior neck pain, extended fever or
palpitation would prevent missing cases of vaccine-related SAT, thereby,
facilitating in time diagnosis and treatment.